From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5FA7AB7CB8 for ; Thu, 14 Jan 2010 20:45:07 +1100 (EST) Subject: Re: [PATCH]: powerpc: Fix build breakage due to incorrect location of autoconf.h From: Benjamin Herrenschmidt To: Joakim Tjernlund In-Reply-To: References: <20100112022150.GE12666@kryten> <20100112140136.c8ccc357.sfr@canb.auug.org.au> <1263412963.724.223.camel@pasglop> <1263459431.724.352.camel@pasglop> Content-Type: text/plain; charset="UTF-8" Date: Thu, 14 Jan 2010 20:43:44 +1100 Message-ID: <1263462224.724.356.camel@pasglop> Mime-Version: 1.0 Cc: Stephen Rothwell , Roel Kluin , "linuxppc-dev@ozlabs.org list" , Richard Purdie , Anton Blanchard , Andrew Morton , David Woodhouse List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2010-01-14 at 10:12 +0100, Joakim Tjernlund wrote: > > No, that was on purpose. If an arch doesn't have efficient unaligned > > accesses, then they should not use the optimization since it will > result > > in a lot of unaligned accesses :-) In which case they are better off > > falling back to the old byte-by-byte method. > > Not quite, it is only 1 of 4 accesses that uses unaligned and > that accesses is only unaligned 50% in average, it might still > be faster. We will never know now. Why ? If you think it's a win, then it's easy to make a patch to turn it to __KERNEL__ and ask some people from ARM and MIPS or even sparc land for example to give it a spin. If it's indeed a win, then submit it to Linus and/or Andrew and there's no reason for it not to go in. I simply took a more conservative approach for post -rc4 Cheers, Ben.